In a typical prior art lipstick dispenser, an elevator cup retains a body of lipstick for axial extension and retraction by a swiveling of a base portion in relation to a body portion of the dispenser. Dispensers have commonly employed a cam member with helical threads formed therealong that is rotatably associated with a tubular inner body. The inner body is normally formed with opposed longitudinal tracks. The elevator cup typically has opposed lugs that are received through the longitudinal track and associated with the helical threads of the cam member. Under this arrangement, a rotation of the cam member in relation to the tubular innerbody induces the desired axial movement of the elevator cup and the retained body of lipstick as the lugs of the elevator cup slide along the helical threads and the longitudinal tracks.
While effective for its essential purpose, this basic lipstick dispensing design has demonstrated plural disadvantages that have been well recognized in the cosmetic industry. For example, there can be axial and radial looseness between the various components of the lipstick dispenser that can lead to a perceived lack of quality of the device and, by inference, the retained product. The lipstick product can also be perceived as being inferior when the swivel torque required to operate the dispenser is excessively light or inconsistent. Still further, a loosely retained elevator cup can wobble thereby resulting in damage to the product and again reducing the perceived quality thereof.
Conversely, it has been found that a lipstick mechanism with a smooth feel and with consistent torque characteristics lends a perception of quality to the device with a resultant increase in the perceived value of the product. A frictional drag of sufficient significance imparts a firm feel to the device that gives an impression of luxury. Preferably, the frictional drag will remain generally constant during extension and retraction of the lipstick and without regard to whether the dispenser is substantially full or substantially exhausted of cosmetic.
Prior art inventors have proposed numerous arrangements for meeting these needs and goals. In one construction, flexible tabs have portions that project radially from the inner body to provide a frictional engagement with the cam or spiral member. That frictional engagement is intended to provide the dispenser with the desired braking effect and constant swivel torque. Other arrangements have produced a similar frictional engagement by the introduction of fins or ribs on the inner body. It has been found, however, that the tabs and ribs can plastically deform over time thereby losing effectiveness. Additionally, certain of these arrangements can yield an inconsistent swivel torque during travel of the elevator cup since the effective diameter of the relatively moveable components can vary along their length thereby changing the frictional drag in an undesirable manner.
The present inventor has proposed improvements in relation to cosmetic dispensers, such as with U.S. Pat. No. 7,325,991 for a Cosmetic Dispenser with Frictional Drag and U.S. Pat. No. 7,500,799 for a Cosmetic Dispenser with Frictional Swivel Action. Under the teachings of the '991 patent, a protuberance, which can be inflexible, projects from a shoulder portion of the inner body and is aligned with a flexible wall segment of a spiral member to produce a frictional drag therebetween. In the '799 patent, frictional draft was produced between a cam member and an adapter member by one or more drag protuberances therebetween.
Nonetheless, it has come to be appreciated that needs remain in the art of extendable and retractable cosmetic dispensers. For example, under many prior art mechanisms, the existence of multiple points or locations for generating frictional torque renders it more difficult to control the torque within desired swivel torque ranges. It has been found that customers typically prefer torque resistance from approximately around 2 in. oz. to 6 in. oz. However, it must also be recognized that there is a torque range required for the filling equipment to function smoothly. If the swivel torque is too high, then the machine may turn the elevator cup out of the track on the spiral cam. If the torque is too low, the cosmetic dispenser will feel cheap, and the elevator cup will have a tendency to move when the dispenser is not in use. Moreover, the swivel toque needs to be high enough to prevent the elevator cup from pushing inadvertently retracting when the consumer applies the pomade.
As suggested above, it is desired that swivel torque be consistent throughout the entire processes of elevating or lowering the elevator cup. Under many prior art constructions, the swivel torque varies during the elevation and retraction of the cup, often because such constructions not only had multiple points of contact but also because some of these contact points were moving. For instance, where bumps on the outside wall of the elevator cup are designed to interfere with inside wall of the inner body, the openness of the top of the inner body would produce less resistance than the closed bottom.
Many manufacturers have resorted to adding lubrication seeking to keep swivel torque within the desired range and to make for a smooth feel during extension and retraction. Even if those benefits are achieved, however, the introduction of lubrication creates other issues. For instance, swivel torque can be rendered undesirably low, and lubricant can sometimes get on to the pomade or on the outside of the case.
With a knowledge of the foregoing, the present inventor has appreciated that there is a need for a cosmetic dispenser capable of exhibiting smooth extension and retraction with substantially consistent swivel torque not only over the course of a given extension and retraction cycle but also over the life of the cosmetic dispenser. It is equally clear that there is a need for such a dispenser that is operative without a need for the introduction of lubricant into the system thereby avoiding the potentially deleterious effects thereof.